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OAF Photo Gallery

This section provides photographs of some of the many factors that can cause the yield in real stands to differ from the yield predicted by TIPSY. These yield differences are reconciled by applying an OAF to predicted yield. Many of these factors and the associated discussion also apply to other stand growth models such as MGM, STIM, FPS, SPS, TASS, PrognosisBC, and Stand Density Management Diagrams. Click on the photograph to view enlarged photo and read the associated text.

 
Image Index
Wood defects
Poor stem form
Root rot pockets
Ponds and swamps
Low density
Disease
Non-commercial cover
EP922.02
Non-productive area
Rock outcrops
Old roads
Senescence
Espacement
Slash

Animal damage
Waste

Wood defects:

Woodpecker damageSome adjustment to predicted yield may be required to account for yield losses to log defects like these woodpecker holes in a live redcedar tree. TIPSY assumes that all trees are solid wood without these kinds of defects. Top



Poor stem form:

ForkedCrookSome adjustment to predicted yield may be required to account for yield losses due to stem defects like a) this forked top on a western larch tree (left) and b) this crook on a lodgepole pine (right). TIPSY assumes that all tree stems have a smooth continuous bole with a single, live top. Top


Root rot pockets:

RootSome adjustment to predicted yield may be required to account for yield losses to diseases like this root rot pocket in a second-growth Douglas-fir stand. TIPSY assumes that stands are relatively—but not completely—disease free. Top

 


Ponds and swamps:

Beaver PondIf you conducted a ground-based survey of this stand and wanted a TIPSY yield prediction for it, you would probably type out this small pond. Thus, you would not need to apply OAF to the predicted yield to account for the pond area. However, if you were working off of the typical forest cover inventory file, this pond would not be identified. Thus, you would need to apply an OAF to the predicted yield to account for the pond area. So, depending on the resolution of your data, some adjustment to predicted yield may be required to account for yield losses due to small water bodies, like this beaver pond in a young lodgepole pine stand. TIPSY assumes that, whatever the density, there are no large holes in the stand. Top


Low density:

Wide spacingWide SpacingNo adjustment to predicted yield is required to account for wide spacing—like the very wide spacing in this young lodgepole pine stand. (Left photo, right photo) TIPSY can predict yield across a wide range of post-spacing densities and will predict reduced yield for wide spacing. As long as there are no large holes in the stand, no further adjustment to predicted yield is necessary to account for the wide spacing, though adjustments may still be required for the other factors illustrated on this web page. Top


Disease:

StemgallLopherdimallaSome adjustment to predicted yield may be required to account for yield losses to disease like a) this gall on an older lodgepole pine, (left) and b) this lodgepole pine that has lost foliage to lophodermella (right). TIPSY assumes that the stand is relatively—but not completely—disease free. Top


Non-commercial cover:

AspenAlderSome adjustment to predicted yield may be required to account for yield losses to small pockets of non-commercial cover like a) this patch of aspen within a young lodgepole pine plantation (left) and b) this alder pocket within a spruce-balsam stand (right). TIPSY assumes that there are no large pockets of non-commercial cover. Top


EP922.02:

EP922.02Some adjustment to predicted yield may be required because TIPSY is calibrated to predict “potential yield”—the yield expected from uniformly stocked, healthy stands. This photo of EP922.02 illustrates several common features of the data used to calibrate TIPSY. Note the high degree of uniformity of site and stocking and the low incidence of forest health damage. Top


Non-productive area:

SlideSome adjustment to predicted yield may be required to account for yield losses to small patches of non-productive land like this slide in the middle of a Douglas-fir plantation. The resolution of your data determines whether you must apply an OAF to predicted yield. If you conducted intensive ground sampling of this polygon and typed out the slide area, you would not need to apply an OAF to predicted yield to account for the non-productive area. However, if your input data was the typical forest cover inventory information, the slide area was too small to show up, and you wanted to apply the predicted yield to the entire polygon, you would need to account for the non-productive slide area by applying an OAF to the predicted yield. Top


Rock outcrops:

Rock OutcropsSome adjustment to predicted yield may be required to account for yield losses to small rock outcrops scattered throughout a polygon, like these small rock outcrops in a lodgepole pine plantation. TIPSY assumes that, whatever the density, there are no large gaps in the stand. Top


Old roads:

Old roadSome adjustment to predicted yield may be required to account for yield losses due to old roads and skid trails, like this old road in the middle of the plantation. The way in which you structure your analysis and prepare your data determines whether you must apply an OAF to predicted yield to account for the old roads. For example, if you make some overall reduction for productive land lost to roads, you will not need to apply an OAF to predicted yield to account for them. Also see the discussion for Ponds and Swamps and Non-Productive Area. Top


Senescence, stand break-up, and succession:

SenesenceSome adjustment to predicted yield may be required to account for yield losses at very old ages in stands that are breaking up, like this old lodgepole pine stand where the overstorey pines are losing vigour and dying out, and spruces and balsams are growing into the canopy. TIPSY assumes that live trees have live, single stem tops, and does not have the capacity to simulate stand break-up and succession. Top


Espacement:

EspacementSome adjustment to predicted yield may be required to account for a difference between the actual inter-tree spacing in a stand and the inter-tree spacing assumed by the TIPSY simulation for that stand. Variation in the spacing between trees is evident in this Douglas-fir plantation. Each TIPSY run assumes a particular pattern of distances between trees. Top


Slash:

SlashpileSome adjustment to predicted yield may be required to account for yield losses if excessive slash loading prohibits seedling establishment, like this landing slash in a recently harvested coastal Douglas-fir stand. TIPSY assumes that to whatever density the stand is regenerated, there are no large piles of slash that prohibit seedling establishment. Top


Animal damage:

Animal DamageElk DamageSome adjustment to predicted yield may be required to account for growth reductions, log defects, and mortality due to animal damage, like a) the damage on this young lodgepole pine tree and b) the elk damage to this Douglas-fir. TIPSY assumes that trees in the stand grow with only low levels of animal damage. Top


Waste:

WasteSome adjustment to predicted yield may be required to account for logging waste if you want TIPSY’s merchantable volume predictions to indicate the volume that will be removed from the site. Use of the appropriate merchantability limits in TIPSY will help, but depending on the characteristics of the trees left as waste, some additional adjustment may be required. TIPSY’s merchantable volume/ha prediction includes the stem volume between stump height and minimum top diameter of all live trees above the minimum diameter. Top

 
Last Updated: February 3, 2006
The contact for this web page is: tim.ebata@gov.bc.ca
BC Ministry of Forests Forest Practices Branch